Bis-phosphinimine catalyst

ABSTRACT

Organometallic complexes having two phosphinimine ligands and at least one activatable ligand are catalyst components for olefin polymerization. Preferred polymerization systems are prepared by combining the organometallic complexes with an ionic activator and/or an alumoxane. Preferred catalyst components contain titanium, zirconium, or hafnium and are activated with an ionic activator to form catalysts for ethylene polymerization.

This is a division of application Ser. No. 09/333,750, filed Jun. 15,1999 U.S. Pat. No. 6,239,238.

FIELD OF THE INVENTION

This invention relates to an olefin polymerization catalyst componentwhich is an organometallic complex having two phosphinimine ligands andat least one activatable ligand. The catalyst component is furthercharacterized by the absence of any cyclopentadienyl ligand.

BACKGROUND OF THE INVENTION

Certain “metallocenes” (especially bis-cyclopentadienyl complexes ofgroup 4 metals) are highly productive catalysts for olefinpolymerization when used in combination with an appropriate activator(see, for example, U.S. Pat. No. (“USP”) 4,542,199 (Sinn et al) and U.S.Pat. No. 5,198,401 (Hlatky and Turner).

Olefin polymerization catalysts having one cyclopentadienyl ligand andone phosphinimine ligand are disclosed in a commonly assigned patentapplication (Stephan et al).

We have now discovered a family of highly active olefin polymerizationcatalysts which do not contain a cyclopentadienyl ligand.

SUMMARY OF THE INVENTION

The present invention provides a catalyst component for olefinpolymerization which is an unbridged bis-phosphinimine complex definedby the formula:

(Pl)₂—M—L_(n)

wherein M is a metal selected from group 3-10 metals; each Pl isindependently a phosphinimine ligand defined by the formula:

wherein each R¹ is independently selected from the group consisting of(a) a hydrogen atom, (b) a halogen atom, (c) C₁₋₂₀ hydrocarbyl radicalswhich are unsubstituted by or further substituted by a halogen atom, (d)a C₁₋₄ ₈ alkoxy radical, (e) a C₆₋₁₀ aryl or aryloxy radical, (f) anamido radical (which may be substituted), (g) a silyl radical of theformula:

—Si—(—R²)₃

wherein each R² is independently selected from the group consisting ofhydrogen, a C₁₋₈ alkyl or alkoxy radical, C₆₋₁₀ aryl or aryloxyradicals, and (h) a germanyl radical of the formula:

Ge—(R²)₃

wherein R² is as defined above; L is an activatable ligand; n is 1, 2 or3 depending upon the valence of M with the proviso that L is not acyclopentadienyl, indenyl or fluorenyl ligand.

DETAILED DESCRIPTION

1. Description of Catalyst Component

The catalyst component of this invention is unbridged. The term“unbridged” is meant to convey its conventional meaning, namely thatthere is not a bridging group which connects the phosphinimine ligandswith formal bonds. (By contrast, many metallocene catalysts having twocyclopentadienyl-type ligands are “bridged” with, for example, adimethyl silyl “bridge” in which the silicon atom is formally bonded toboth of the cyclopentadienyl ligands). “Unbridged” catalyst componentsare typically less expensive to synthesize than the correspondingbridged analogues.

1.1 Metals

The catalyst component of this invention is an organometallic complex ofa group 3, 4, 5, 6, 7, 8, 9 or 10 metal (where the numbers refer tocolumns in the Periodic Table of the Elements using IUPAC nomenclature).The preferred metals are selected from groups 4 and 5, especiallytitanium, hafnium, zirconium or vanadium.

1.2 Phosphinimine Ligand

The catalyst component of this invention must contain a phosphinimineligand which is covalently bonded to the metal. This ligand is definedby the formula:

wherein each R¹ is independently selected from the group consisting of ahydrogen atom, a halogen atom, C₁₋₂₀ hydrocarbyl radicals which areunsubstituted by or further substituted by a halogen atom, a C₁₋₈ alkoxyradical, a C₆₋₁₀ aryl or aryloxy radical, an amido radical, a silylradical of the formula:

—Si—(R²)₃

wherein each R² is independently selected from the group consisting ofhydrogen, a C₁₋₈ alkyl or alkoxy radical, C₆₋₁₀ aryl or aryloxyradicals, and a germanyl radical of the formula:

Ge—(R²)₃

wherein R² is as defined above.

The preferred phosphinimines are those in which each R¹ is a hydrocarbylradical. A particularly preferred phosphinimine is tri-(tertiary butyl)phosphinimine (i.e. where each R¹ is a tertiary butyl group).

1.3 Activatable Ligand

The term “activatable ligand” refers to a ligand which may be activatedby a cocatalyst (also known as an “activator”) to facilitate olefinpolymerization. Exemplary activatable ligands are independently selectedfrom the group consisting of a hydrogen atom, a halogen atom, a C₁₋₁₀hydrocarbyl radical, a C₁₋₁₀ alkoxy radical, a C₅₋₁₀ aryl oxide radical;each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may beunsubstituted by or further substituted by a halogen atom, a C₁₋₈ alkylradical, a C₁₋₈ alkoxy radical, a C₆₋₁₀ aryl or aryl oxy radical, anamido radical which is unsubstituted or substituted by up to two C₁₋₈alkyl radicals; a phosphido radical which is unsubstituted orsubstituted by up to two C₁₋₈ alkyl radicals.

The activatable ligands must not be cyclopentadienyl ligands (or relatedligands such as indenyl or fluorenyl).

The number of activatable ligands depends upon the valency of the metaland the valency of the activatable ligand. The preferred catalyst metalsare group 4 metals in their highest oxidation state (i.e. 4⁺) and thepreferred activatable ligands are monoanionic. Thus, the preferredcatalyst components contain two phosphinimine ligands and two(monoanionic) activatable ligands bonded to the group 4 metal. In someinstances, the metal of the catalyst component may not be in the highestoxidation state. For example, a titanium (III) component would containonly one activatable ligand.

2. Description of Activators (or “Cocatalysts”)

The catalyst components described in part 1 above are used incombination with an “activator” (which may also be referred to by aperson skilled in the art as a “cocatalyst”) to form an active catalystsystem for olefin polymerization. Simple aluminum alkyls and alkoxidesmay provide comparatively weak cocatalytic activity under certain mildpolymerization conditions. However, the preferred activators arealumoxanes and so-called ionic activators, as described below.

2.1 Alumoxanes

The alumoxane activator may be of the formula:

(R⁴)₂AlO(R⁴AlO)_(m)Al(R⁴)₂

wherein each R⁴ is independently selected from the group consisting ofC₁₋₂₀ hydrocarbyl radicals and m is from 0 to 50, preferably R⁴ is aC₁₋₄ alkyl radical and m is from 5 to 30. Methylalumoxane (or “MAO”) isthe preferred alumoxane.

Alumoxanes are well known as activators for metallocene-type catalysts.

Activation with alumoxane generally requires a molar ratio of aluminumin the activator to (group 4) metal in the catalyst from 20:1 to 1000:1.Preferred ratios are from 50:1 to 250:1.

2.2 Ionic Activators

Ionic activators are also well known for metallocene catalysts. See, forexample, U.S. Pat. No. 5,198,401 (Hlatky and Turner). These compoundsmay be selected from the group consisting of:

(i) compounds of the formula [R⁵]⁺[B(R⁷)₄]⁻ wherein B is a boron atom,R⁵ is a cyclic C₅₋₇ aromatic cation or a triphenyl methyl cation andeach R⁷ is independently selected from the group consisting of phenylradicals which are unsubstituted or substituted with from 3 to 5substituents selected from the group consisting of a fluorine atom, aC₁₋₄ alkyl or alkoxy radical which is unsubstituted or substituted by afluorine atom; and a silyl radical of the formula —Si—(R⁹)₃; whereineach R⁹ is independently selected from the group consisting of ahydrogen atom and a C₁₋₄ alkyl radical; and

(ii) compounds of the formula [(R⁸)_(t)ZH]⁺[B(R⁷)₄]⁻ wherein B is aboron atom, H is a hydrogen atom, Z is a nitrogen atom or phosphorusatom, t is 2 or 3 and R⁸ is selected from the group consisting of C₁₋₈alkyl radicals, a phenyl radical which is unsubstituted or substitutedby up to three C₁₋₄ alkyl radicals, or one R⁸ taken together with thenitrogen atom may form an anilinium radical and R⁷ is as defined above;and

(iii) compounds of the formula B(R⁷)₃ wherein R⁷ is as defined above.

In the above compounds preferably R⁷ is a pentafluorophenyl radical, andR⁵ is a triphenylmethyl cation, Z is a nitrogen atom and R⁸ is a C₁₋₄alkyl radical or R⁸ taken together with the nitrogen atom forms ananilinium radical which is substituted by two C₁₋₄ alkyl radicals.

The “ionic activator” may abstract one or more activatable ligands so asto ionize the catalyst center into a cation but not to covalently bondwith the catalyst and to provide sufficient distance between thecatalyst and the ionizing activator to permit a polymerizable olefin toenter the resulting active site.

Examples of ionic activators include:

triethylammonium tetra(phenyl)boron,

tripropylammonium tetra(phenyl)boron,

tri(n-butyl)ammonium tetra(phenyl)boron,

trimethylammonium tetra(p-tolyl)boron,

trimethylammonium tetra(o-tolyl)boron,

tributylammonium tetra(pentafluorophenyl)boron,

tripropylammonium tetra(o,p-dimethylphenyl)boron,

tributylammonium tetra(m,m-dimethylphenyl)boron,

tributylammonium tetra(p-trifluoromethylphenyl)boron,

tributylammonium tetra(pentafluorophenyl)boron,

tri(n-butyl)ammonium tetra(o-tolyl)boron,

N,N-dimethylanilinium tetra(phenyl)boron,

N,N-diethylanilinium tetra(phenyl)boron,

N,N-diethylanilinium tetra(phenyl)n-butylboron,

N,N-2,4,6-pentamethylanilinium tetra(phenyl)boron,

di-(isopropyl)ammonium tetra(pentafluorophenyl)boron,

dicyclohexylammonium tetra(phenyl)boron,

triphenylphosphonium tetra(phenyl)boron,

tri(methylphenyl)phosphonium tetra(phenyl)boron,

tri(dimethylphenyl)phosphonium tetra(phenyl)boron,

tropillium tetrakispentafluorophenyl borate,

triphenylmethylium tetrakispentafluorophenyl borate,

benzene (diazonium) tetrakispentafluorophenyl borate,

tropillium phenyltrispentafluorophenyl borate,

triphenylmethylium phenyltrispentafluorophenyl borate,

benzene (diazonium) phenyltrispentafluorophenyl borate,

tropillium tetrakis (2,3,5,6-tetrafluorophenyl) borate,

triphenylmethylium tetrakis (2,3,5,6-tetrafluorophenyl) borate,

benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,

tropillium tetrakis (3,4,5-trifluorophenyl) borate,

benzene (diazonium) tetrakis (3,4,5-trifluorophenyl) borate,

tropillium tetrakis (1,2,2-trifluoroethenyl) borate,

triphenylmethylium tetrakis (1,2,2-trifluoroethenyl) borate,

benzene (diazonium) tetrakis (1,2,2-trifluoroethenyl) borate,

tropillium tetrakis (2,3,4,5-tetrafluorophenyl) borate,

triphenylmethylium tetrakis (2,3,4,5-tetrafluorophenyl) borate, and

benzene (diazonium) tetrakis (2,3,4,5-tetrafluorophenyl) borate.

Readily commercially available ionic activators include:

N,N-dimethylaniliumtetrakispentafluorophenyl borate;

triphenylmethylium tetrakispentafluorophenyl borate; and

trispentafluorophenyl borane.

3. Homogeneous or Heterogeneous Catalyst

The catalyst system of this invention may be used in a homogeneous formin solution polymerization (where the term “homogeneous” means that thecatalyst and cocatalyst/activator are soluble in, or miscible with, thepolymerization solvent). However, when the catalyst is employed in aslurry or gas phase polymerization, it is highly preferred to use thecatalyst in a heterogeneous or “supported form”. It is also highlypreferred that the catalyst does not cause reactor fouling. The art ofpreparing heterogeneous catalysts which do not lead to reactor foulingis not adequately understood, though it is generally accepted that thecatalytic material should be very well anchored to the support so as toreduce the incidence of fouling resulting from the deposition ofcatalyst or cocatalyst which has dissociated from the support.

In general, heterogeneous catalysts may be grouped into three maincategories:

3.1. Unsupported Alumoxane/Catalyst Mixtures

These catalysts may be easily prepared by evaporating the solvent ordiluent from a liquid mixture of an alumoxane and the catalystcomponent. The resulting product is a solid at room temperature due tothe comparatively high molecular weight of the alumoxane. There are twodisadvantages to this approach, namely cost (i.e. alumoxanes arecomparatively expensive—and the alumoxane is used as an expensive“support” material) and “reaction continuity/fouling” (i.e. thealumoxane may partially melt under polymerization conditions, leading toreactor instability/fouling), U.S. Pat. No. (USP) 4,752,597 (Turner, toExxon) illustrates this approach for the preparation of a heterogeneouscatalyst.

3.2. Metal Oxide Supported Catalysts

These catalysts are prepared by depositing the catalyst component and acocatalyst on a very porous metal oxide support. The catalyst andcocatalyst are substantially contained within the pore structure of themetal oxide particle. This means that a comparatively large metal oxideparticle is used (typically particle size of from 40 to 80 microns). Thepreparation of this type of supported catalyst is described in U.S. Pat.No. 4,808,561 (Welborn, to Exxon).

3.3. Filled/Spray Dried Catalysts

This method of catalyst preparation is also well known. For example,U.S. Pat. Nos. 5,648,310; 5,674,795 and 5,672,669 (all to Union Carbide)teach the preparation of a heterogeneous catalyst by spray drying amixture which contains a metallocene catalyst, an alumoxane cocatalystand a “filler” which is characterized by having a very small particlesize (less than one micron) and by being unreactive with the catalystand cocatalyst. The examples illustrate the use of very fine particlesize “fumed” silica which has been treated to reduce the concentrationof surface hydroxyls. The resulting catalysts exhibit good productivity.Moreover, they offer the potential to provide a catalyst which is notprone to “hot spots” (as the catalyst may be evenly distributed, at lowconcentration, throughout the heterogeneous matrix). However, thesecatalysts suffer from the potential disadvantage of being very friablebecause they are prepared with a fine, “inert” filler material whichdoes not react with/anchor to the catalyst or cocatalyst.

Friable catalyst particles lead to the formation of “fines” in thepolyethylene product, and may also aggravate reactor fouling problems.

An alternative approach is the preparation of spray dried catalystsusing a hydrotalcite as a “reactive” filler (as opposed to theunreactive filler described in the above-mentioned USP to UnionCarbide). This method of catalyst preparation is described in moredetail in a commonly assigned patent application. Either approach issuitable for use with the catalysts of this invention.

4. Polymerization Processes

The catalysts of this invention are suitable for use in any conventionalolefin polymerization process, such as the so-called “gas phase”,“slurry”, “high pressure” or “solution” polymerization processes.

The use of a heterogeneous catalyst is preferred for gas phase andslurry processes whereas a homogeneous catalyst is preferred for thesolution process.

The polymerization process according to this invention uses ethylene andmay include other monomers which are copolymerizable therewith such asother alpha olefins (having from three to ten carbon atoms, preferablybutene, hexene or octene) and, under certain conditions, dienes such ashexadiene isomers, vinyl aromatic monomers such as styrene or cyclicolefin monomers such as norbornene.

The present invention may also be used to prepare elastomeric co- andterpolymers of ethylene, propylene and optionally one or more dienemonomers. Generally, such elastomeric polymers will contain about 50 toabut 75 weight % ethylene, preferably about 50 to 60 weight % ethyleneand correspondingly from 50 to 25% of propylene. A portion of themonomers, typically the propylene monomer, may be replaced by aconjugated diolefin. The diolefin may be present in amounts up to 10weight % of the polymer although typically is present in amounts fromabout 3 to 5 weight %. The resulting polymer may have a compositioncomprising from 40 to 75 weight % of ethylene, from 50 to 15 weight % ofpropylene and up to 10 weight % of a diene monomer to provide 100 weight% of the polymer. Preferred but not limiting examples of the dienes aredicyclopentadiene, 1,4-hexadiene, 5-methylene-2-norbornene,5-ethylidene-2-norbornene and 5-vinyl-2-norbornene. Particularlypreferred dienes are 5-ethylidene-2-norbornene and 1,4-hexadiene.

The polyethylene polymers which may be prepared in accordance with thepresent invention typically comprise not less than 60, preferably notless than 70 weight % of ethylene and the balance one or more C₄₋₁₀alpha olefins, preferably selected from the group consisting of1-butene, 1-hexene and 1-octene. The polyethylene prepared in accordancewith the present invention may be linear low density polyethylene havingdensity from about 0.910 to 0.935 g/cc. The present invention might alsobe useful to prepare polyethylene having a density below 0.910 g/cc—theso-called very low and ultra low density polyethylenes.

The most preferred polymerization process of this invention encompassesthe use of the novel catalysts (together with a cocatalyst) in a mediumpressure solution process. As used herein, the term “medium pressuresolution process” refers to a polymerization carried out in a solventfor the polymer at an operating temperature from 100 to 320° C.(especially from 120 to 220° C.) and a total pressure of from 3 to 35mega Pascals. Hydrogen may be used in this process to control (reduce)molecular weight. Optimal catalyst and cocatalyst concentrations areaffected by such variables as temperature and monomer concentration butmay be quickly optimized by non-inventive tests.

Further details concerning the medium pressure polymerization processare well known to those skilled in the art and widely described in theopen and patent literature.

The catalyst of this invention may also be used in a slurrypolymerization process or a gas phase polymerization process.

The typical slurry polymerization process uses total reactor pressuresof up to about 50 bars and reactor temperature of up to about 200° C.The process employs a liquid medium (e.g. an aromatic such as toluene oran alkane such as hexane, propane or isobutane) in which thepolymerization takes place. This results in a suspension of solidpolymer particles in the medium. Loop reactors are widely used in slurryprocesses. Detailed descriptions of slurry polymerization processes arewidely reported in the open and patent literature.

In general, a fluidized bed gas phase polymerization reactor employs a“bed” of polymer and catalyst which is fluidized by a flow of monomerwhich is at least partially gaseous. Heat is generated by the enthalpyof polymerization of the monomer flowing through the bed. Unreactedmonomer exits the fluidized bed and is contacted with a cooling systemto remove this heat. The cooled monomer is then re-circulated throughthe polymerization zone together with “make-up” monomer to replace thatwhich was polymerized on the previous pass. As will be appreciated bythose skilled in the art, the “fluidized” nature of the polymerizationbed helps to evenly distribute/mix the heat of reaction and therebyminimize the formation of localized temperature gradients (or “hotspots”). Nonetheless, it is essential that the heat of reaction beproperly removed so as to avoid softening or melting of the polymer (andthe resultant and highly undesirable—“reactor chunks”). The obvious wayto maintain good mixing and cooling is to have a very high monomer flowthrough the bed. However, extremely high monomer flow causes undesirablepolymer entrainment.

An alternative (and preferable) approach to high monomer flow is the useof an inert condensable fluid which will boil in the fluidized bed (whenexposed to the enthalpy of polymerization), then exit the fluidized bedas a gas, then come into contact with a cooling element which condensesthe inert fluid. The condensed, cooled fluid is then returned to thepolymerization zone and the boiling/condensing cycle is repeated.

The above-described use of a condensable fluid additive in a gas phasepolymerization is often referred to by those skilled in the art as“condensed mode operation” and is described in additional detail in U.S.Pat. No. 4,543,399 and U.S. Pat. No. 5,352,749. As noted in the '399reference, it is permissible to use alkanes such as butane, pentanes orhexanes as the condensable fluid and the amount of such condensed fluidpreferably does not exceed about 20 weight per cent of the gas phase.

Other reaction conditions for the polymerization of ethylene which arereported in the '399 reference are:

Preferred Polymerization Temperatures: about 75° C. to about 115° C.(with the lower temperatures being preferred for lower meltingcopolymers—especially those having densities of less than 0.915 g/cc—andthe higher temperatures being preferred for higher density copolymersand homopolymers); and

Pressure: up to about 1000 psi (with a preferred range of from about 100to 350 psi for olefin polymerization).

The '399 reference teaches that the fluidized bed process is welladapted for the preparation of polyethylene but further notes that othermonomers may be employed—as is the case in the process of thisinvention.

EXAMPLES

The invention will now be illustrated in further detail by way of thefollowing non-limiting examples. For clarity, the Examples have beendivided into three parts, namely Part A (Catalyst Component Synthesis),Part B (Solution Polymerization) and Part C (Gas Phase Polymerization).

Polymer Analysis

Gel permeation chromatography (“GPC”) analysis was carried out using acommercially available chromatograph (sold under the name Waters 150GPC) using 1,2,4-trichlorobenzene as the mobile phase at 140° C. Thesamples were prepared by dissolving the polymer in the mobile phasesolvent in an external oven at 0.1% (weight/volume) and were run withoutfiltration. Molecular weights are expressed as polyethylene equivalentswith a relative standard deviation of 2.9% and 5.0% for the numberaverage molecular weight (Mn) and weight average molecular weight (Mw),respectively. Melt index (MI) measurements were conducted according toASTM method D-1238-82.

Polymer densities were measured using pressed plaques (ASTM methodD-1928-90), with a densitometer.

The following abbreviations are used in the Examples:

^(t)Bu=tertiary butyl (e.g. ^(t)Bu₃=tri-tertiary butyl)

Me=methyl

Et=ethyl

¹H NMR=proton nuclear magnetic resonance

^(i)Pr=isopropyl

Ph=phenyl

Mw=weight average molecular weight

Mn=number average molecular weight

PD=polydispersity (or Mw/Mn)

PE=polyethylene

Cat=catalyst

Hr=hour

M=molar

PART A Catalyst Component Synthesis

A.1 Synthesis of (^(t)Bu₃PN)(^(i)Pr₃PN)TiCl₂

^(i)Pr₃P═N—SiMe₃ (0.6 g, 2.43 mmol) was added to a toluene solution (˜60mL) of ^(t)Bu₃PNTiCl₃. The solution was refluxed at 120° C. (bathtemperature) for 45 hours and was concentrated to ˜3 mL. The product wascrystallized at −70° C. after the solution was mixed with heptane (˜10mL). The yield was 0.87 g, 85%. ¹H NMR (δ, C₇D₈): 1.78 (m, 3H), 1.351(dd, J₁=13.0 Hz, J₂=1.2 Hz, 27H), 1.064 (dd, J₁=14.8 hz, J₂=7.19 Hz,18H).

A.2 Methylation of (^(t)Bu₃PN)(^(i)Pr₃PN)TiCl₂

MeMgBr in diethyl ether (3M, 0.75 mL, 2.2 mmol) was added to a toluenesolution (˜20 mL) of (^(t)Bu₃PN)(^(i)Pr₃PN)TiCl₂ (0.509 g, 1 mmol). Themixture was stirred for 1 hour, the volatiles were stripped off byvacuum pumping and the remaining solid was extracted with hexane (3×15mL). The hexane extract was pumped to dryness and a crystalline solidwas obtained. The identity of the product was proved to be(^(t)Bu₃PN)₂TiMe₂. ¹H NMR (δ, C₇D₈): 1.379 (d, J=12.5 Hz, 54H), 0.777(s, 6H). The result was further verified by two independent reactions.The residual solid was treated with Me₃SiCl in ether, pumped to drynessand was extracted with hexane again. The extract was pumped to drynessand the residue was checked with NMR which showed the resonance(doublets of doublet) of ^(i)Pr₃P fragment and two other resonances.There was no resonance due to the ^(t)Bu₃PN ligand.

A.3 Synthesis of (^(i)Pr₃PN)₂TiCl₂

^(i)Pr₃P═N—SiMe₃ (0.990 g, 4.0 mmol) was added to a toluene solution(˜60 mL) of TiCl₄ (0.380 g, 2 mmol). The solution was refluxed for 1hour and a brown solution formed. 25 mg of anhydrous Na₂SO₄ (acceleratesthe reaction) was then added to the solution which was refluxedovernight. A transparent, light blue solution formed. The solution wasfiltered to remove a slight amount of solid and was pumped to dryness.An almost white solid was obtained (quantitative yield). ¹H NMR showedthat the product is pure. ¹H NMR (δ, C₇D₈): 1.80 (m, 6H), 1.06 (dd,J₁=14.8 Hz, J₂=7.20 Hz, 36 H).

A.4 Synthesis of (^(i)Pr₃PN)₂TiMe₂

MeMgBr in diethyl ether (3.0 M, 0.7 mL, 2.0 mmol) was added to a toluenesolution (20 mL) of (^(i)Pr₃PN)₂TiCl₂ (0.467 g, 1 mmol). The mixture wasstirred for about 1 hour and volatiles were removed under vacuum. Theresidue was extracted with hexane (3×20 mL) and the extract was slowlypumped to dryness. The product was obtained as a white crystalline solid(420 mg, ˜100%). ¹H NMR (δ, C₇D₈): 2.27 (m, 6H), 1.40 (dd, J₁=15.3 HZ,J₂=7.24 Hz, 36H), 0.867 (s, 6H).

A.5 Synthesis of bis(tri-t-butylphosphinimine)zirconiumdibenzyl

A solution of tri-t-butylphosphinimine (868 mg, 4 mmol) in toluene (20mL) was added dropwise to a solution of tetrabenzylzirconium (910 mg, 2mmol) in toluene (80 mL) at 10° C. The reaction was warmed to roomtemperature and stirred for five minutes. The toluene was removed invacuo and the resulting oil dissolved in hexane (30 mL). The solutionwas filtered and the hexane removed in vacuo to leave an oil thatcrystallized as a white solid on standing at room temperature forseveral hours. Yield 1.115 g. The product was pure by ¹H NMRspectroscopy except for a small amount of unreactedtri-t-butylphosphinimine. 1H (C₇D₈): 7.17-6.80 (multiplet), 2.23 (s),1.22 (d, ³J_(P-H)=12.4 Hz).

A.6 Synthesis of bis(tri-t-butylphosphinimine)titanium dichloride

To a solution of titanium tetrachloride (336 mg; 1.77 mmol) in toluene(20 mL) was added solid tri-t-butylphosphinimine-N-trimethylsilyl (1.025g, 3.55 mmol). The reaction was heated to 110° C. overnight and then thetoluene was removed in vacuo. The product was taken up in fresh toluene,filtered and concentrated. The product crystallized out as a pureproduct. Yield 0.664 g. 1H (C₇D₈): 1.33 (d, J_(P-H)=12.7 Hz).

A.7 Synthesis of bis(tri-t-butylphosphinimine)titanium dimethyl

To a slurry of bis(tri-t-butylphosphinimine)titanium dichloride (340 mg;0.62 mmol) in ether (15 mL) was added MeMgBr (0.7 mL, 3 M, 2.1 mmol) at−78° C. The reaction was stirred at room temperature 20 minutes beforethe volatiles were removed in vacuo. The product was extracted withhexane, the reaction filtered and the hexane removed to yield a whitecrystalline solid. Yield 280 mg, 90%. 1 H (C₇D₈): 1.37(d, J_(P-H)=12.5Hz), 0.77 (s).

PART B Solution Polymerization

Solution polymerizations were completed either in a Solution BatchReactor (“SBR”) or in a continuous reaction. The “SBR” experiments aredescribed in Part B.1 and the continuous experiments in Part B.2.

B.1 SBR Experimental Conditions

The SBR uses a programmable logical control (PLC) system with Wonderware5.1 software for process control. Ethylene polymerizations wereperformed in a 500 mL Autoclave Engineers Zipperclave reactor equippedwith an air driven stirrer and an automatic temperature control system.All the chemicals were fed into the reactor batchwise except ethylenewhich was fed on demand.

Typical experimental conditions for screening experiments are tabulatedbelow.

Cyclohexane 216 mL Catalyst Concentration 200 μmol/L Activator 210μmol/L Scavenger • PMAO-IP 1 mmol/L put into the reactor with 216 mLreaction solvent. • PMAO-IP 1 mmol/L dissolved in 250 mL of cyclohexaneas the scavenger, the solution was stirred for 10 minutes at roomtemperature, then withdrawn with a canula before the reaction solventwas loaded in Reaction Temperature 160° C. Reactor Pressure 140 psigtotal Stirring Speed 2000 mm Comonomer 10 or 20 mL of octene Notes: 1.Table B.1 identifies the borane or borate activator used in eachexperiment. 2. “PMAO-IP” is a commercially available methylalumoxane.

TABLE B.1 Activity (g PE/ Mw (*10⁻³) Run # Catalyst Activator mmol {cat}Hr) and PD 10404 Me₂Ti(NP^(t)Bu₃)₂ (1) [CPh₃][B(C₆F₅)₄] 2430.8 114.4(2.6) 10402 (NP^(t)Bu₃)₂Zr(CH₂Ph)₂ (2) [CPh₃][B(C₆F₅)₄] 377.15 1.84 (1.8Branch/ 1-octene Activity (g PE/ Mw (*10⁻³) 1000C Run # (mL) CatalystActivator mmol {cat} Hr) and PD (density) 10406 20 Me₂Ti(NP^(t)Bu₃)₂ (1)[CPh₃][B(C₆F₅)₄] 2039.8 18.7 (5.5) 57 (0.866) 10413 20 Me₂Ti(NP^(t)Bu₃)₂(1) [NHMe₂Ph][B(C₆F₅)₄] 3407.4 29.7 (7.0) 63 (0.886) 10419 10Me₂Ti(NP^(t)Bu₃)₂ (1) [NHMe₂Ph][B(C₆F₅)₄] 4672.1 60.0 (5.6) 26.6 1040920 Me₂Ti(NP^(t)Bu₃)₂ B(C₆F₅)₃ 2784.9 25.0 (4.4) 34.3 (0.886) Notes: (1)Catalyst from Part A, Section A.7 (2) Catalyst from Part A, Section A.5

B.2 Continuous Solution Polymerization

All the polymerization experiments described below were conducted on acontinuous solution polymerization reactor. The process is continuous inall feed streams (solvent, monomers and catalyst) and in the removal ofproduct. All feed streams were purified prior to the reactor by contactwith various absorption media to remove catalyst killing impurities suchas water, oxygen and polar materials as is known to those skilled in theart. All components were stored and manipulated under an atmosphere ofpurified nitrogen.

All the examples below were conducted in a reactor of 71.5 cc internalvolume. In each experiment the volumetric feed to the reactor was keptconstant and as a consequence so was the reactor residence time.

The catalyst solutions were pumped to the reactor independently andthere was no pre-contact between the activator and the catalyst. Becauseof the low solubility of the catalysts, activators and MAO incyclohexane, solutions were prepared in purified xylene. The catalystwas activated in situ (in the polymerization reactor) at the reactiontemperature in the presence of the monomers. The polymerizations werecarried out in cyclohexane at a pressure of 1500 psi. Ethylene wassupplied to the reactor by a calibrated thermal mass flow meter and wasdissolved in the reaction solvent prior to the polymerization reactor.If comonomer (for example 1-octene) was used it was also premixed withthe ethylene before entering the polymerization reactor. Under theseconditions the ethylene conversion is a dependent variable controlled bythe catalyst concentration, reaction temperature and catalyst activity,etc.

The internal reactor temperature is monitored by a thermocouple in thepolymerization medium and can be controlled at the required set point to+/−0.5 C. Downstream of the reactor the pressure was reduced from thereaction pressure (1500 psi) to atmospheric. The solid polymer was thenrecovered as a slurry in the condensed solvent and was dried byevaporation before analysis.

The ethylene conversion was determined by a dedicated on-line gaschromatograph by reference to propane which was used as an internalstandard. The average polymerization rate constant was calculated basedon the reactor hold-up time, the catalyst concentration in the reactorand the ethylene conversion and is expressed in l/(mmol*min). Averagepolymerization rate (kp)=(Q/(100-Q))×(1/[TM])×(1/HUT),

where:

Q is the percent ethylene conversion;

[TM] is the catalyst concentration in the reactor expressed in mM; and

HUT is the reactor hold-up time in minutes.

Polymer Analysis

Melt index (Ml) measurements were conducted according to ASTM methodD-1238-82.

Polymer densities were measured on pressed plaques (ASTM D-1928-90) witha densitometer.

Example 1

[(^(t)Bu)₃PN)]₂TiMe₂ (from Part A, Section A.7) was added to the reactorat 9.3×10⁻⁶ mol/l along with Ph₃C B(C₆F₅)₄ (Asahi Glass) at B/Ti=1.00(mol/mol). The reaction temperature was 160° C. and 2.1 gram/min ofethylene was continuously added to the reactor. An ethylene conversionof 99.6% was observed (see Table B.2).

Example 2

[(^(t)Bu)₃PN)]₂TiMe₂ (from Part A, Section A.7) was added to the reactorat 9.3×10⁻⁶ mol/l along with MAO (MMAO-7 Akzo Nobel) at Al/Ti=50(mol/mol). The reaction temperature was 160° C. and 2.1 gram/min ofethylene was continuously added to the reactor. An ethylene conversionof approximately 10% was observed (see Table B.2).

Example 3

[(^(t)Bu)₃PN)]₂TiMe₂ (from Part A, Section A.7) was added to the reactorat 9.3×10⁻⁶ mol/l along with Ph₃C B(C₆F₅)₄ (Asahi Glass) at B/Ti=1.00(mol/mol). The reaction temperature was 200° C. and 3.8 gram/min ofethylene was continuously added to the reactor. An ethylene conversionof 90.1% was observed (see Table B.2).

Example 4

[(^(t)Bu)₃PN)]₂TiMe₂ (from Part A, Section A.7) was added to the reactorat 4.6×10⁻⁶ mol/l along with Ph₃C B(C₆F₅)₄ (Asahi Glass) at B/Ti=0.5(mol/mol). The reaction temperature was 160° C. and 2.1 gram/min ofethylene was continuously added to the reactor. In addition 1.0 ml/minof 1-octene was also added. An ethylene conversion of 90.4% was observed(see Table B.2).

Example 5

[(^(t)Bu)₃PN)]₂TiMe₂ (from Part A, Section A.7) was added to the reactorat 4.6×10⁻⁶ mol/l along with Ph₃C B(C₆F₅)₄ (Asahi Glass) at B/Ti=0.5(mol/mol). The reaction temperature was 160° C. and 2.1 gram/min ofethylene was continuously added to the reactor. In addition 3.0 ml/minof 1-octene was also added. An ethylene conversion of 88.0% was observed(see Table B.2).

Comparative Example A

(C₅Me₅)₂ZrCl₂ (purchased from Strem) was added to the reactor at 37×10⁻⁶mol/l along with MMAO-3 (Akzo-Nobel, Al/Ti=400 mol/mol). The reactiontemperature was 140° C. and 1.0 gram/min of ethylene was continuouslyadded to the reactor. An ethylene conversion of 55.5% was observed (seeTable B.3).

Comparative Example B

(C₅Me₅)₂ZrCl₂ (Strem) was added to the reactor at 37×10⁻⁶ mol/l alongwith MMAO-3 (Akzo-Nobel, Al/Ti=400 mol/mol). The reaction temperaturewas 160° C. and 1.0 gram/min of ethylene was continuously added to thereactor. An ethylene conversion of 35.6% was observed (see Table B.3).

Comparative Example C

(C₅Me₅)₂ZrCl₂ (Strem) was added to the reactor at 37×10⁻⁶ mol/l alongwith MMAO-3 (Akzo-Nobel, Al/Ti=400 mol/mol). The reaction temperaturewas 160° C. and 2.1 gram/min of ethylene was continuously added to thereactor. An ethylene conversion of 37.4% was observed (see Table B.3).

Comparative Example D

rac-Et(ind)₂ZrCl₂ (purchased from Witco) was added to the reactor at37×10⁻⁶ mol/l along with MMAO-3 (Akzo-Nobel, Al/Ti=400 mol/mol). Thereaction temperature was 160° C. and 2.1 gram/min of ethylene wascontinuously added to the reactor. An ethylene conversion of 94.6 % wasobserved (see Table B.3).

Comparative Example E

rac-Et(ind)₂ZrCl₂ (Witco) was added to the reactor at 37×10⁻⁶ mol/lalong with MMAO-3 (Akzo-Nobel, Al/Ti=400 mol/mol). The reactiontemperature was 160° C. and 2.1 gram/min of ethylene and 3.25 ml/min of1-octene was continuously added to the reactor. An ethylene conversionof 94.8% was observed (see Table B.3).

TABLE B.2 Total Calculated Flow to Catalyst Ethylene PolymerizationPolymer Polymer Reactor Concentration Conversion Rate (kp) Density MeltMn × Mw × Example (ml/min) (mol/l × 10⁶) (%) (l/mmol × min) (g/cc) Index10⁻³ 10⁻³ 1 27.0 9.3 99.6 9444 — — — — 2 27.0 9.3 10 4.5 — — — — 3 27.09.3 90.1 372 0.957 3.03 25.8 51.2 4 27.0 4.6 90.4 767 0.917 24.9 19.838.4 5 27.0 4.6 88.0 560 0.895 445 — —

TABLE B.3 Total Calculated Flow to Catalyst Ethylene PolymerizationPolymer Polymer Reactor Concentration Conversion Rate (kp) Density MeltMn × Mw × Example (ml/min) (mol/l × 10⁶) (%) (l/mmol × min) (g/cc) Index10⁻³ 10⁻³ A^(c) 27.0 37.0 55.5 13 — 880 2.7 10.0 B^(c) 27.0 37.0 35.6 6— — 1.8 7.5 C^(c) 27.0 37.0 37.4 6 — 620 3.3 12.0 D^(c) 27.0 37.0 94.6179 — 1300 3.9 14.0 E^(c) 27.0 37.0 94.8 186 0.925 very high 2.6 10.0^(c)Comparative

PART C Gas Phase Polymerization

Catalyst Preparation and Polymerization Testing Using a Semi-Batch, GasPhase Reactor

The catalyst preparation methods described below employ typicaltechniques for the syntheses and handling of air-sensitive materials.Standard Schlenk and drybox techniques were used in the preparation ofthe supported catalysts. Solvents were purchased as anhydrous materialsand further treated to remove oxygen and polar impurities by contactwith a combination of activated alumina, molecular sieves and copperoxide on silica/alumina. Where appropriate, elemental compositions ofthe supported catalysts were measured by Neutron Activation analysis anda reported accuracy of ±1% (weight basis).

The supported catalysts were prepared by initially supporting MAO on asilica support, followed by deposition of the catalyst component.

All the polymerization experiments described below were conducted usinga semi-batch, gas phase polymerization reactor of total internal volumeof 2.2 L. Reaction gas mixtures, including separately ethylene orethylene/butene mixtures, were measured in the reactor on a continuousbasis using a calibrated thermal mass flow meter, following passagethrough purification media as described above. A pre-determined mass ofthe catalyst sample was added to the reactor under the flow of the inletgas with no pre-contact of the catalyst with any reagent, such as acatalyst activator. The catalyst was activated in situ (in thepolymerization reactor) at the reaction temperature in the presence ofthe monomers, using a metal alkyl complex which has been previouslyadded to the reactor to remove adventitious impurities. Purified andrigorously anhydrous sodium chloride was used as a catalyst dispersingagent.

The internal reactor temperature was monitored by a thermocouple in thepolymerization medium and can be controlled at the required set point to±1.0° C. The duration of the polymerization experiment was one hour.Following the completion of the polymerization experiment, the polymerwas separated from the sodium chloride and the yield determined.

Table C illustrates data concerning the Al/transition metal ratios ofthe supported catalyst, polymer yield and polymer properties.

TABLE C mmol Support mg of Yield gPe/g gPe/g AI/M Complex Complex *Catalyst g Metal Catalyst ratio [N=P(¹Bu)₃]₂TiCl₂ 28 mg 0.5 55 0.5 18989.1 91.20 (0.0508 mmol) Notes: 1. Support is silica treated with MAO(purchased from Witco) 2. Ethylene-Butene copolymerization (Co) 4 mol. %1-Butene 3. Pe = Polyethylene 4. The catalyst is from Part A, SectionA.6

What is claimed is:
 1. A catalyst component for olefin polymerizationwhich is an unbridged bis-phosphinimine complex defined by the formula:(Pl)₂—M—L_(n) wherein M is a metal selected from group 2-14 10 metals;each Pl is independently a phosphinimine ligand defined by the formula:

wherein each R¹ independently selected from the group consisting of (a)a hydrogen atom, (b) a halogen atom, (c) C₁₋₂₀ hydrocarbyl radicalswhich are (i) unsubstituted or (ii) further substituted by a halogenatom, (d) a C₁₋₈ alkoxy radical, (e) a C₆₋₁₀ aryl or aryloxy radical,(f) an amido radical, (g) a silyl radical of the formula: —Si—(R²)₃wherein each R² independently selected from the group consisting ofhydrogen, a C₁₋₈ alkyl or alkoxy radical, C₆₋₁₀ aryl and C₆₋₁₀ aryloxyradicals, and (h) a germanyl radical of the formula: Ge—(R²)₃ wherein R²is as defined above; L is an activatable ligand; n is 1, 2 or 3depending upon the valence of M with the proviso that L is not acyclopentadienyl, indenyl or fluorenyl ligand; and B an activator. 2.The catalyst component according to claim 1 wherein M is selected fromgroup 4 and group 5 metals.
 3. The catalyst component according to claim2 wherein each L is independently selected from the group consisting ofa hydrogen atom, a halogen atom, a C₁₋₁₀ hydrocarbyl radical, a C₁₋₁₀alkoxy radical, a C₅₋₁₀ aryl oxide radical; each of which saidhydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by orfurther substituted by a halogen atom, a C₁₋₈ alkyl radical, a C₁₋₈alkoxy radical, a C₆₋₁₀ aryl or aryl oxy radical, an amido radical whichis unsubstituted or substituted by up to two C₁₋₈ alkyl radicals; aphosphido radical which is unsubstituted or substituted by up to twoC₁₋₈ alkyl radicals.
 4. The catalyst component according to claim 1wherein M is titanium (III) and n is
 1. 5. The catalyst componentaccording to claim 1 wherein each R¹ is independently a hydrocarbylgroup containing from one to twenty carbon atoms.
 6. The catalystcomponent according to claim 1 wherein each R¹ is tertiary-butyl.
 7. Anolefin polymerization catalyst system comprising a catalyst componentaccording to claim 1 and an activator.
 8. The catalyst system accordingto claim 7 wherein said activator is an alumoxane.
 9. The catalystsystem according to claim 8 wherein each R¹ is tertiary butyl, n is 2and each of said L is a halide.
 10. The catalyst system according toclaim 7 wherein said activator is an ionic activator.
 11. The catalystsystem according to claim 10 wherein each R¹ is tertiary butyl, said Mis titanium, n is 2 and each of said L is a hydrocarbyl group havingfrom one to twenty carbon atoms.
 12. The catalyst system according toclaim 10 wherein said ionic activator comprises an organometallic boroncomplex containing one boron atom and at least three perfluorinatedphenyl ligands bonded to said boron atom.
 13. The catalyst systemaccording to claim 11 wherein each of said L is methyl.
 14. The catalystsystem according to claim 12 which further contains alumoxane.